Aphid Alert 2002, No. 1, July 2

Aphid Situation, July 2

Through June 29, no green peach aphid were captured in traps at any location in the 2002 Aphid Alert Network. However, spring 2002 has seen five major wind events (low level jets) likely to have brought green peach aphid to the Northern Great Plains. At the Rosemount Agricultural Experiment Station, we have found that ~1/3 of the leaves of potato plants already support green peach aphid apterae. We strongly encourage potato growers, especially seed potato producers, to closely monitor their fields and apply effective aphicides at first detection of green peach aphid colonization.

Subscriber Alert

This is the first issue of Aphid Alert 2002. This newsletter is intended to alert seed potato producers in the Northern Great Plains to flight activity by aphid species that are known to be potential vectors of potato viruses. As in previous years, we will report results weekly on the WWW, by e-mail to subscribers, and by surface mail to all Minnesota and North Dakota seed potato growers. To become an e-mail subscriber send us an e-mail message with the word "subscribe" in subject line. We have taken the liberty of adding many names to our e-mail subscriber list. If you have no interest in receiving this newsletter by e-mail please reply with the word "unsubscribe" in the subject line. Some e-mail subscribers may not wish to receive messages containing graphics, if so reply with the the words "no graphics" in the subject line.

Figure: Spring 2002 has seen five major wind events (low level jets) likely to have brought green peach aphid to the Northern Great Plains. The first of these occurred May 21-23 and was of 36 h duration (Fig. 1), the second occurred June 8-10 and was of 42 h duration (Fig. 2), the third occurred June 18-19 and was of 24 h duration, the fourth was June 21-23 and was of 45 h duration, and the most recent was June 29-30 and was of 36 h duration (Fig. 5). No winged green peach aphids have yet been caught in our traps, but colonizing green peach aphid were abundant on potatoes at Rosemount on July 1.

Figure: Cumulative captures of green peach aphid (per trap), 1992-1994, and 1998-2001. Three distinctly different seasonal patterns of green peach aphid abundance have been observed. In 1998 and 1999 green peach aphid were abundant with total captures approximately an order of magnitude greater (10X) than that of 1992, 1993 and 1994, and two orders of magnitude greater (100X) than that of 1993 and 2001. For the Minnesota and North Dakota seed potato industry, low green peach aphid pressure in 1994 coincided with the end of a multi-year PVY epidemic and the low green peach aphid pressure of 2001 coincided with the end of a multi-year epidemic of PLRV.